A generic sensor arrangement and a generic rolling bearing arrangement are known from WO 2011/134955 A2. The generic rolling bearing arrangement is illustrated in a perspective cross-sectional representation in the appended FIG. 2. To begin with, the rolling bearing arrangement includes a rolling bearing 01, to which an angle sensor 02 is attached, axially adjacent thereto. Rolling bearing 01 includes an inner ring 03 and an outer ring 06, which is rotatable around inner ring 03 around a rotation axis 04. Rolling elements 07 in the form of balls are situated between inner ring 03 and outer ring 06. Rolling elements 07 are held in a cage 08 (illustrated in FIG. 3). The space between outer ring 06 and inner ring 03 is sealed to the outside by a sealing washer 09.
Angle sensor 02 includes a sensor ring 11, which is fastened on outer ring 06 in a circumferential groove 13 provided in outer ring 06, with the aid of a holding element 12. However, sensor ring 11 is not rotatably fixedly fastened on outer ring 06, since annular holding element 12 is able to rotate around rotation axis 04 in circumferential groove 13. The rotatably non-fixed design of the fastening is due to the circumstance that outer ring 06 is slightly rotated in the machine element (not illustrated) accommodating outer ring 06 during a longer operation. Due to the rotatably non-fixed design of the fastening, sensor ring 11 may retain its angle position on rotation axis 04, so that the measurements using the angle sensor are not corrupted.
Angle sensor 02 furthermore includes a material measure 14, which is rotatably fixedly fastened to inner ring 03 in a circumferential groove 16 provided in inner ring 03. Material measure 14 has an eccentric annular shape and is illustrated in detail in FIGS. 9 and 10. Material measure 14 closes the U-shaped cross-sectional shape of a U-shaped pot core 17, which is fastened in sensor ring 11. Annular pot core 17 is made of a ferromagnetic material. The U-shaped cross section of pot core 17 forms an inner U-leg 18 and an outer U-leg 19, which are angled against a U-base 21.
Sensor ring 11 includes an inner supporting ring 22 and an outer supporting ring 23, an annular space 24 being provided between inner supporting ring 22 and outer supporting ring 23, in which pot core 17 and a p.c. board 26 are situated. P.c. board 26 is shown in detail in FIG. 4. A transmitter coil 27 (illustrated in FIG. 4) and receiver coils 28 (illustrated in FIG. 4) are provided on p.c. board 26. Transmitter coil 27 and receiver coil 28 are electrically connectable with the aid of a cable 29. Cable 29 is guided to the outside of annular space 24 through a recess 32 in outer supporting ring 23 with the aid of a cable holder 31 on pot core 17. Cable holder 31 is furthermore used to rotatably fixedly fix pot core 17 and p.c. board 26 with respect to the machine element (not illustrated) accommodating the rolling bearing arrangement.
FIG. 3 shows a cross-sectional representation of the rolling bearing arrangement illustrated in FIG. 2.
FIG. 4 shows a detailed representation of p.c. board 26 illustrated in FIG. 2. Transmitter coil 27 and receiver coils 28 are provided on p.c. board 26. P.c. board 26 is a printed-circuit board which includes multiple layers, transmitter coil 27 and receiver coil 28 being designed as printed conductors 36. P.c. board 26 has four evenly distributed openings 37 of the same design. Openings 37 each have the shape of a circular ring segment. The circular ring segments each have a center point angle of approximately 60°. Outer U-leg 19 of pot core 17 is guided through openings 37, so that pot core 17 completely surrounds transmitter coil 27, while it surrounds receiver coils 28 only approximately halfway. Outer U-leg 19, which has an annular design, is interrupted in its annular shape, so that it is able to project through openings 37. Due to the interruptions in the annular shape of outer U-leg 19, ring segments 38 are provided, each of which has the shape of a circular arc. Circular arcs each have a center point angle of approximately 60°.
FIG. 9 shows one embodiment of a material measure 14, which is known from the prior art for the rolling bearing arrangement illustrated in FIG. 2. Material measure 14 is illustrated in a cross-sectional view perpendicularly to rotation axis 04, outer U-leg 19 and inner U-leg 18 furthermore being shown. During a rotation of material measure 14 with respect to pot core 17 (illustrated in FIG. 2), the material measure results in a variable reluctance of the magnetic circuit formed by pot core 17 and material measure 14 with regard to individual receiver coils 28 (illustrated in FIG. 4), since material measure 14 is provided with an eccentric design. The eccentricity of material measure 14 is due to the fact that a ring width of annular material measure 14 circumferentially changes, namely from a minimum ring width to a maximum ring width and back to a minimum ring width.
FIG. 10 shows a detailed view of material measure 14 illustrated in FIG. 2. In contrast to the material measure illustrated in FIG. 9, material measure 14 in FIG. 10 has a double eccentric design, since both the outer circumference of material measure 14 and the inner circumference of material measure 14 have an eccentric design. As a result, the angle sensor is less susceptible to movements of U-legs 18, 19 perpendicular to rotation axis 04.
The design of ring segments 38 (shown in FIG. 4) is not illustrated for outer U-legs 19 illustrated in FIG. 9 and FIG. 10.
The rolling bearing arrangement shown in WO 2011/134955 A2 facilitates absolute angle measurements between 0° and 360°. As a result, it is suitable, for example, for supporting a shaft of a monopolar electric motor. Angle sensor 02 illustrated in FIGS. 2 through 4 is therefore also characterized as being monopolar.